De Wijk Member

Code
NLDOWY
Status
Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1997). Renamed (2019).
Lithological description

Tuffaceous clay and silt, blue to violet-grey in colour, alternating with dark-grey and red-brown clay. Contains volcanic ashes originated from a source located N(W) of the North Sea (Morton & Knox, 1990).

Depositional setting

Marine.

Definition of lower boundary

Can be distinguished from the under- and overlying rock units by its characteristic wire-line log expression, consisting of a somewhat lower gamma-ray reading than the average clay, and by its high-velocity peaks on the acoustic log (Jacqué & Thouvenin 1975).

Definition of upper boundary

Can be distinguished from the under- and overlying rock units by its characteristic wire-line log expression, consisting of a somewhat lower gamma-ray reading than the average clay, and by its high-velocity peaks on the acoustic log (Jacqué & Thouvenin 1975).

Thickness indication
Tens of meters.
Geographical distribution
Regional correlation
UK: Balder Formation; GER: ?; BEL: not present.
Age
early Eocene (Ypresian).
Holostratotype
Depth (thickness) AH:
1524 - 1532 m AH (8 m)
Lectostratotype
Well:
De Wijk-17 (WYK-17)
Depth (thickness) AH:
510-535 m AH (25 m)
Origin of name
Named after the village of Wijk in the northeast of the Netherlands.
Previous name(s)
Basal Dongen Tuffite Member (Van Adrichem Boogaert & Kouwe 1997). The name "Dongen" is already in use as formation name.
Reviewed by (date)
Geert-Jan Vis (2019).
References
Jacqué, M. and Thouvenin, J., 1975: Lower Tertiary tuffs and volcanic activity in the North Sea. In: Woodland, A.W. (ed.): Petroleum and the continental shelf of North West Europe, I Geology, p. 455-465 - Applied Science Publ., Barking.
Morton, A.C. and Knox, R.W.O'B, 1990: Geochemistry of late Paleocene and early Eocene tephras from the North Sea Basin - Journ. Geol. Soc. London, 147, p. 425-437.
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1997. Stratigraphic nomenclature of The Netherlands, revision and update by RGD and NOGEPA, Section I, Tertiary. Mededelingen Rijks Geologische Dienst, 50, 1-39.
Cite as
TNO-GDN ([YEAR]). De Wijk Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/de-wijk-member.